Unsaturated ketones and their use in perfumery

ABSTRACT

The compounds according to the general formula                    
     in which formula the dotted lines indicate a single or a double bond, n and m are 0 or 1, R 1  is hydrogen or an acyl group —C(O)R 3 , R 3  being a linear or branched alkyl or alkylene group from C 1  to C 8 , the oxygen atom being bound to the adjacent α-carbon atom by a double bond in the case where n is 0 and by a single bond in the case where n is 1, R 2  is hydrogen or a linear or branched alkyl, alkenyl or alkoxy group from C 1  to C 8 , or R 2  is an alkenoxy group which is linked to the group R 1  to form a 1,3-dioxolane cycle having 5 to 7 ring members, are useful perfuming ingredients. The most preferred compounds according to the invention are those which have a damascone- or damascenone-like structure, with the methyl substituent being in 4-position of the ring instead of the 2-position, as is the case in damascones and damascenones.

BRIEF SUMMARY OF THE INVENTION

The present invention relates to the field of perfumery. It relates,more particularly, to compounds derived from the4,4,6-trimethylcyclohexane skeleton and being represented by thestructure according to the general formula (I)

in which formula the dotted lines indicate a single or a double bondwhich may optionally be present in the molecule, n and m are 0 or 1, R¹is hydrogen or an acyl group —C(O)R³, R³ being a linear or branchedalkyl or alkylene group from C₁ to C₈, or a substituted or unsubstitutedphenyl group, the oxygen atom being bound to the adjacent α-carbon atomby a double bond in the case where n is 0 and by a single bond in thecase where n is 1, R² is hydrogen or a linear or branched alkyl, alkenylor alkoxy group from C₁ to C₈, or R² is an alkenoxy group which islinked to the group R¹ to form a 1,3-dioxolane cycle having 5 to 7 ringmembers.

BACKGROUND OF THE INVENTION

The compounds according to the above formula (I) form a novel class offragrant molecules the use of which has never been proposed inperfumery. In fact, there exist in this field classes of compoundsderived from a cyclohexane ring which carries three methyl substituents,but with a different substitution pattern, as shown in formula (II), inwhich the dotted lines indicate a double bond which may optionally bepresent in the C₆-ring and R is an organic rest carrying, for example, aketo function

DETAILED DESCRIPTION OF THE INVENTION

As is clear from a comparison of the two formulae (I) and (II), thecompounds known from the prior art are 2,6,6-trimethyl-substituted,which is in contrast to the 4,6,6-trimethyl substitution of thecompounds according to the present invention. Well-known examples forthe compounds according to formula (II) are damascones and damascenone,in which case R is a —(O)C—CH═CH—CH₃ group and the ring carries onedouble bond in the 1-, 2- or 3-position for damascones, and two doublebonds in the 1- and 3-position for damascenone.

To our great surprise, and in spite of the structural ressemblance ofthe compounds known in the art with the class of molecules according tothe present invention and outlined in the above formula (I), we were thefirst to establish the perfumistic value of these said compounds.

The base molecule which serves as starting product for the synthesis ofthe class of compounds according to formula (I) is4,6,6-trimethyl-1,3-cyclohexadiene-1-carbaldehyde, which has for thefirst time been described by A. F. Thomas et al. in Helv. Chim. Acta 59(1976), p. 2261-7. As is shown in the scheme (1) below, this compound isthen converted into the desired products by the introduction offunctional groups, eventually after hydrogenation of one or both of thecarbon-carbon double bonds in the C₆-ring. As a consequence, the dottedlines in the molecules shown in the scheme below indicate theseoptionally present double bonds. The reference to the synthesis of therespective compounds in the scheme below is not limiting, refering onlyto examples for the preparation of the respective class of compounds.The symbols R⁴-R⁷ in the scheme (1) will be defined further below, inthe paragraphs refering to the respective classes of compounds. Theclasses of molecules shown in scheme (1) are preferred according to thepresent invention.

a) reduction (e.g. NaBH₄, LiAlH₄)

b) esterification (e.g. carboxylic acid, anhydride or halide)

c) acetalization (e.g. divalent alcohol)

d) Grignard reagent/hydrolysis; then oxidation [e.g. manganese dioxide,pyridinium dichromate (PDC) or pyridinium chlorochromate (PCC)]

The mentioned carbaldehydes (III) in the above scheme are themselves ofperfumistic value. In particular, the2,2,4-trimethyl-1-cyclohexanecarbaldehyde shows a nice, fresh, aldehyde-and thuyone-like odor with a green connotation reminiscent of Zestover(2,4-dimethyl-3-cyclohexene-1-carbaldehyde; origin: Firmenich SA) and3,5,5-trimethylhexanal.

The alcohols (IV), obtainable from the above carbaldehydes by reductionof the carbonyl function, show olfactory notes which are different fromthose of the latter, with the aldehyde note being totally absent.4,6,6-Trimethyl-1,3-cyclohexadiene-1-methanol has a balsamic-woody notewith an incense type connotation being present, somewhat typical of theodor inside a church. The corresponding saturated alcohol, i.e.2,2,4-trimethyl-1-cyclohexanemethanol, has an odor composed of green andearthy, borneol-camphoraceous-pinanol notes, with a minty connotationbeing also found.

Another interesting group of compounds, from an olfactory point of view,are the acetals (VI), obtainable from the above-mentioned aldehydes(III) by acetalization. In the above formula (VI), R⁵ and R⁶ can beidentical or different and are hydrogen or a linear or branched alkylgroup from C₁ to C₆, and n is an integer from 1 to 3. They show woody,fruity and spicy odors, the most interesting compound being4-methyl-2-(4,6,6-trimethyl-1-cyclohexen-1-yl)-1,3-dioxolan. The odor ofthis latter is of the woody-camphoraceous type with a strong liquoriceundernote, pleasant and appreciated by perfumers.

The esters according to the formula (V) in the above scheme, in which R⁴is a linear or branched alkyl group from C₁ to C₈ or a substituted orunsubstituted phenyl group, have odors of the floral type which areaccompanied by undernotes which vary depending on the structure. Amongstthe said esters, one preferred compound is(4,4,6-trimethyl-1,3-cyclohexadien-1-yl)methyl isobutyrate which has acomplex odor profile, being composed of notes reminiscent ofIsopentyrate (1,3-dimethyl-3-butenyl isobutyrate; origin: Firmenich SA),i.e. fruity-floral with a camomile connotation. There are furtherperceived notes which are typical of damascones, butyrates andcarbinols, with a base note of Estragol® (1-allyl-4-methoxybenzene;origin: Givaudan-Roure SA, Vernier, Switzerland). Two other preferredesters are (4,6,6-trimethyl-1-cyclohexen-1-yl)methyl acetate and—butanoate. The acetate has a jasmine note with fruity amylicconnotations, whereas the odor of the butanoate is remiscent of orris,with a ionone undernote. Finally, another preferred ester is(2,2,4-trimethyl-1-cyclohexyl)methyl acetate which shows an odor profilreminiscent of Dorysil (4-tert-butyl-1-cyclohexyl acetate; origin:Firmenich SA), i.e. of the fruity-jasmine type, and methylionones, witha woody-hazelnut connotation.

The α,β-unsaturated ketones according to the general formula (VII) inwhich R⁷ is a linear or branched alkyl or alkylene group from C₁ to C₄are compounds of perfumistic importance. They are structurally relatedto the well-known damascones or damascenones, but can olfactively beclearly distinguished from these, also due to various pleasant andappreciated undernotes which are not known in combination with thedamascone, respectively damascenone-type note which is always found inthe molecules according to formula (VII). In general, thedamascone-damascenone type odor is accompanied by fruity undernotes. Thesynthesis and the odor of the compounds according to formula (VII) inwhich R⁷ is a methyl group and which has one double bond in position 3of the cycle is described by V. M. Andreev et al in Hydrolysis and WoodChem. 1993, p 23-25.

The preferred type of compounds within the group described by thegeneral formula (VII) are the α,β-unsaturated ketones which obey to thegeneral formulae (VIII) and (IX)

wherein R⁷ is a linear or branched alkyl or alkenyl group from C₁ to C₄,and which may be in the form of the isomer of the (E) or (Z)configuration, or a mixture of the two.

The compounds of this type are not described in the chemical literature,and the difference between the said compounds and the already mentioneddamascones and, respectively damascenones, lies in the position of themethyl substituent at the C₆-ring [position 2 for the damascones anddamascenones, position 4 for the compounds according to the invention]The damascones and damascenones are highly-appreciated perfumingingredients, in particular1-(2,6,6-trimethyl-1,3-cyclohexen-1-yl)-2-buten-1-one,1-(2,6,6-trimethyl-1,3-cyclohexen-2-yl)-2-buten-1-one, and1-(2,6,6-trimethyl-1,3-cyclohexadien-1-yl)-2-buten-1-one. This lattercompound is found in the oil of the bulgarian rose, and its synthesis,as well as the synthesis of its homologues, is described in the patentU.S. Pat. No. 3,931,326 (assignee: Firmenich SA). The odor of theabove-mentioned damascenone forms an own olfactive class in the familyof the floral-rose odors, and its olfactive profile is described asbeing very complex. Olfactive descriptors which are often used arefruity, floral-exotic, reminiscent of the odor of cassis and plums.

However, to our great surprise and in spite of the structural similarityof the compounds (VII) according to the present invention with thedamascones and damascenones, we could not find in the chemicalliterature any mention or even a synthesis for this class of compounds.

We have found that the odor of the compounds (VIII) is quite distinctfrom that of the damascenones, bringing thus new olfactive notes to theperfumers' palette. In spite of the presence of a typicaldamascenone-like undernote, the overall olfactive impression is howeverdominated by other olfactive notes which result in a heretofore unknown,complex odor, wherein spicy, saffron-type, fruity and mirabelle-typeodors are quite prononced, however, it is in particular thewoody-agarwood type character which is remarkable and dominant.

As an example, there is cited here the compound of formula (VIII) inwhich R is a methyl group, in particular the isomer of(E)-configuration, or(E)-1-(4,6,6-trimethyl-1,3-cyclohexadien-1-yl)-2-buten-1-one, which isthe preferred compound of the invention. The olfactive profile of thismolecule is composed of the typical damascenone odor, which isaccompanied by a mirabelle accord and, in surplus, a strongwoody-saffron note. There are also found a celery type connotation aswell as a complex base note, with fruity and floral connotations,reminiscent of jasmine.

The combination of the above-described olfactive characteristics isunique, and the palette of perfuming ingredients which are at theperfumers' disposal is thus enriched by the compounds according to theinvention, in particular(E)-1-(4,6,6-trimethyl-1,3-cyclohexadien-1-yl)-2-buten-1-one.

Of course, the use of(E)-1-(4,6,6-trimethyl-1,3-cyclohexadien-1-yl)-2-buten-1-one inperfumery is not restricted to this isomer, it can also be used in formof a mixture with the (Z)-isomer. The proportion of this latter isomerwhich may be present in in such mixtures depends on the desiredolfactive effect, and the person skilled in the art will be perfectlyable to choose the desired amount. We have found that mixturescontaining at least 90% by weight of the (E) isomer and at most 10% byweight of the (Z)-enatiomer are as advantageous, from an olfactive pointof view, the pure (E)-enantiomer.

Like for the compounds of formula (VIII), we could find that thecompounds of formula (IX) have odors distinct from those of their knownanalogs, i.e. the so-called β-damascones. Their odor profile is quitecomplex, and there are found, besides a typical damascone note which isalways present, spicy and resinous notes.

More particulary, the compound according to formula (IX) in which R is amethyl group shows an odor typical of damascone which is accompanied bya strong saffron note. The perfumes could also perceive a floralundernote combined with a spicy connotation of the incense-resinoustype, quite original and unknown heretofore.

The compounds according to the present invention can be used inpractically every field of modem perfumery. There are cited here theapplications in fine perfumery, i.e. in the preparations of perfumes andcolognes in which new and original effects can be obtained.

The compounds can also be used in functional perfumery. Non-limitingexamples for this type of application include soaps, bath and showergels, shampoos, deodorants and antiperspirants, air fresheners, liquidand solid detergents for the treatment of textiles and fabric softeners.

In these applications, they can be used alone or in admixture with otherperfuming ingredients, solvents or adjuvants of current use inperfumery. The nature and the variety of these coingredients do notrequire a more detailed description here, which, moreover, would not beexhaustive, and the person skilled in the art will be able to choose thelatter through its general knowledge and as a function of the nature ofthe product to be perfumed and of the desired olfactive effect. Theseperfuming ingredients belong to chemical classes as varied as alcohols,aldehydes, ketones, esters, ethers, acetates, nitrites, terpenehydrocarbons, sulfur- and nitrogen-containing heterocyclic compounds, aswell as essential oils of natural or synthetic origin. A large number ofthese ingredients is moreover listed in reference textbooks such as thebook of S. Arctander, Perfume and Flavor Chemicals, 1969, Montclair,N.J., USA, or its more recent versions, or in other works of similarnature.

The proportions in which the compounds according to the invention can beincorporated in the various products mentioned beforehand vary within alarge range of values. These values depend on the nature of the articleor products that one desires to perfume and the olfactive effectsearched for, as well as on the nature of the coingredients in a givencomposition when the compound of the invention is used in admixture withperfuming coingredients, solvents or adjuvants of current use in theart.

As an example, and again with reference to the compounds of formula(VII), there can be cited typical concentrations of the order of 0.1 to1%, or even more, by weight of this compound relative to the weight ofthe perfuming composition in which it is incorporated. Far lowerconcentrations than those mentioned can be used when the compound isdirectly applied for the perfuming of the various consumer productscited beforehand.

The invention will now be described in a more detailed manner in thefollowing examples in which the abbreviations have the usual meaning inthe art and the temperatures are given in degrees Celsius.

EXAMPLE 1 Preparation of 4,6,6-trimethyl-1-cyclohexene-1-carbaldehyde

A mixture of 4,6,6-trimethyl-1,3-cyclohexadiene-1-carbaldehyde (141 g,0.94 mole), ethanol (1 l) and palladium on charcoal (10%, 0.5 g) washydrogenated by shaking under a H₂-atmosphere for 3.5 h. TheH₂-consumption was 23.5 l. After filtration and concentration of thethus-obtained solution, the residue was distilled at 50°/0.7 hPa, toobtain 125.3 g (87.6%) of the desired product.

Odor: terpenes, metallic. MS: 152(M⁺, 59), 137(42), 123(78), 109(77),95(48), 81(83), 67(94), 41(100); ¹H-NMR: 1.0(d, J=6.5 Hz, 3H); 1.17(s,3H); 1.23(s, 3H); 6.67(dd, J₁=2 Hz, J₂=6 Hz); 9.35(s, 1H) δ (ppm).

EXAMPLE 2 Preparation of 2,2,4-trimethyl-1-cyclohexanecarbaldehyde

4,6,6-Trimethyl-1,3-cyclohexadiene-1-carbaldehyde (100.0 g, 0.66 mole),11 of ethyl acetate and 0.3 g of palladium on charcoal (0.3 g) werehydrogenated as described in Example 1, over 3 days. The H₂-consumptionwas 35 1. The mixture was then heated with pyridin chlorochromate tooxidize the amounts of alcohol formed. After filtration andconcentration, the product was distilled at 65-73°/18 hPa, to obtain68.8 g (67%) of the desired product in the form of a mixture of 2isomers in a ratio of 1:3.

MS: 154(M⁺, 6), 139(13), 121(11), 110(26), 95(25), 83(66), 69(67),55(74), 41(100); MS (main isomer): 154(M⁺, 7), 139(11), 121(10),110(27), 95(22), 83(74), 69(93), 41(100); ¹H-NMR: 0.86(main isomer) and0.89(two d, J=6.5 Hz), 0.97 and 1.13 (main isomer, two s) and 1.03 and1.08(two s), 9.8 (main isomer) and 9.92 (two d, J=0.4 Hz) δ (ppm).

EXAMPLE 3 Preparation of 4,6,6-trimethyl-1,3-cyclohexadiene-1-methanol

A solution of 20 g (133 mole) of4,6,6-trimethyl-1,3-cyclohexadiene-1-carbaldehyde in 100 ml ofdiethylether was added to a suspension of 1.5 g (39 mmole) of LiAlH₄ indiethylether, under stirring and cooling with an ice-bath. After 1 h ofreaction time, the mixture was hydrolyzed, the organic layer wasseparated, washed and dried and concentrated. The crude product was thendistilled in vacuo, b.p. 60°/20 hPa, to obtain 11.6 g (56%) of thedesired product.

MS: 152(M⁺, 36), 121(78), 107(100), 91(52), 77(24), 39(17); ¹H-NMR:1.02(s, 6H); 1.78(broad s, 3H); 1.98(broad s, 2H); 4.18(broad s, 2H);5.63 and 5.81(two m, 2H) δ (ppm).

EXAMPLE 4 Preparation of 4,6,6-trimethyl-1,3-cyclohexene-1-methanol

The procedure described in the above Example 3 was repeated, using 20.7g (0.136 ml) of 4,6,6-trimethyl-1-cyclohexene-1-carbaldehyde and 1.7 g(0.44 mmole) of LiAlH₄ in 200 ml of diethyl ether. Distillation at70°/0.6 hPa afforded 20.9 g (99%) of pure product.

MS: 154(M⁺, 17), 139(26), 123(100), 93(67), 81(74), 55(58), 41(95);¹H-NMR: 0.93(d, J=7 Hz, 3H); 1.03(s, 3H); 1.09(s, 3H); 4.12(broad s,2H); 5.64(m, 1H) δ (ppm); ¹³C-NMR: 22.3(q); 25.3(d); 28.5(q); 28.8(q);34.4(s); 34.6(t); 48.7(t); 63.3(t); 122.9(d); 144.4(s) δ (ppm).

EXAMPLE 5 Preparation of 2,2,4-trimethyl-1-cyclohexanemethanol

The procedure described in the above Example 3 was repeated, using 20 g(0.13 mole) of 2,2,4-trimethyl-1-cyclohexanecarbaldehyde and 1.7 g (45mmole) of LiAlH₄ in 200 ml of diethyl ether. Distillation at 50°/0.5 hPaafforded 18.6 g (92%) of pure product, composed of about 90% of transand 10% of cis-isomer.

MS: (trans, main isomer): 156(M⁺, 3), 141(20), 136(17), 123(78), 95(28),83(100), 69(73), 55(37), 41(30); (cis, minor isomer): 156(M⁺, 5),141(9), 138(10), 123(55), 95(27), 83(100), 69(75), 55(40), 41(30);¹H-NMR: 0.78(s, 3H); 0.83 (d, J=7, 3H); 0.97(s, 3H); 3.3(dd, J₁=10,J₂=12, 1H); 3.85(dd, J₁=2.4, J₂=10, 1H) δ (ppm); ¹³C-NMR: 20.5(q);22.8(q); 25.9(t); 28.2(d); 30.9(q); 32.9(q); 35.1(t); 48.9(d); 51.6(t);64.5(t) δ (ppm).

EXAMPLE 6 Preparation of (4,4,6-trimethyl-1,3-cyclohexadien-1-yl)methylisobutyrate

A mixture of 4,4,6-trimethyl-1,3-cyclohexadiene-1-methanol (1.9 g, 12.5mmole) and pyridine (5 ml) was cooled (ice bath) and stirred, thenisobutyryl chloride (1.9 ml, 18 mmol) was added dropwise. After stirringovernight at room temperature, the reaction mixture was poured onto ice,extracted with pentane, washed with HCl (10%), NaHCO₃ (5%) and brine.

Distillation at a bath temperature of 80°/0.4 hPa afforded 2.17 g (78%)of pure product.

MS: 222(M⁺, 12), 134(20), 119(100), 105(20), 91(26), 71(24), 43(53);¹H-NMR: 1.02(s, 6H); 1.18(d, J=6.5 Hz, 6H); 1.78(s, 3H); 2.0(s, 2H);2.57(hept, 1H); 4.6(s, 2H); 5.64(m, 1H); 5.85(d, J=5 Hz) δ (ppm).

EXAMPLE 7 Preparation of (4,6,6-trimethyl-1-cyclohexen-1-yl)methylacetate

A mixture of 4,6,6-trimethyl-1-cyclohexene-1-methanol (3 g, 19.5 mmole)and acetic anhydride (2.4 g, 24 mmole) was heated to 70° during 3 h,then distilled at a bath temperature of 70°/0.5 hPa, to obtain 3.27 g(86%) of the desired product.

MS: 196(M⁺, 3), 154(34), 139(32), 121(72), 93(55), 79(42), 43(100);¹H-NMR: 0.94(d, J=7 Hz, 3H); 1.2(s, 3H); 1.08(s, 3H); 2.07(s, 3H);4.55(s, 2H); 5.67(m, 1H) δ (ppm); ¹³C-NMR: 21.2(q); 22.2(q); 25.1(d);28.3(q); 28.6(q); 34.5(s); 34.6(t); 48.4(t); 65.5(t); 126.9(d);139.2(s); 170.9(s) δ (ppm).

EXAMPLE 8 Preparation of (4,6,6-trimethyl-1-cyclohexen-1-yl)methylbutyrate

The procedure described in Example 7 was repeated, using 3.7 g (24mmole) of butyric anhydride. After distillation at a bath temperature of100°/0.5 hPa, 3.74 g (86%) of pure product were obtained.

MS: 224 (M⁺, 5), 154(57), 139(62), 121(87), 93(66), 71(61), 43(100);¹H-NMR: 0.93(d, J=7 Hz, 3H); 0.94(tr, J=7 Hz, 3H); 1.02(s, 3H); 1.08(s,3H); 1.67(q, J=7 Hz, 2H); 4.53(s, 2H); 5.66(m, 1H) δ (ppm); ¹³C-NMR:13.7(q); 18.5(t); 22.2(q); 25.1(a); 28.4(q); 28.7(q); 34.5(s); 34.6(t);36.5(t); 48.5(t); 65.3(t); 126.7(d); 139.3(s); 173.5(s) δ (ppm).

EXAMPLE 9 Preparation of4-methyl-2-(4,6,6-trimethyl-1-cyclohexen-1-yl)-1,3-dioxolan

4,6,6-Trimethyl-1-cyclohexen-1-carbaldehyde (2 g, 13 mmole),1,2-propanediol (4 g, 53 mmole) and p-toluenesulfonic acid (50 mg) wererefluxed in 20 ml of toluene, with water separation in a Dean-Starkapparatus, during 6 h. The resulting solution was washed with a NaHCO₃solution and the crude product distilled at a bath temperature of80°/0.5 hPa, to obtain 1.78 g of the desired product in the form of amixture of isomers.

MS (main peak): 210 (M⁺, 28), 195(22), 153(100), 113(26), 87(30),59(20), 41(15); ¹H-NMR: 0.93(d, J=6.5 Hz, 3H); 1.1(s, 3H); 1.13(s, 3H);6.0 and 6.05(two m, 1H) δ (ppm).

EXAMPLE 10 Preparation of 1-(2,2,4-trimethyl-1-cyclohexyl)-2-buten-1-one

2,2,4-Trimethyl-1-cyclohexanecarbaldehyde (11 g, 72 mmole) in ether (100ml) was added dropwise with stirring to a Grignard compound preparedfrom Mg (2.3 g) and allylbromide (10 g) in ether and refluxed for 2 h.After cooling, the mixture was hydrolyzed with NH₄Cl-solution, thendistilled at a bath temperature of 150°/0.5 hPa, to obtain 11.3 g (80%)of the desired product as a 2:1 mixture of 2 isomers.

MS (main isomer): 194 (M⁺, 0), 163(1), 155(28), 137(76), 111(46),95(56), 81(72), 69(60), 57(100), 41(97);

MS (minor isomer): 194 (M⁺, 0), 163(1), 155(25), 137(76), 111(45),95(50), 81(67), 69(76), 57(88), 41(100); ¹H-NMR: 0.82(minor isomer) and0.83(main isomer) (two d, J=7 Hz, 3H); 0.87& 1.07(minor isomer) two sand 0.93 & 0.97(main isomer) two s; 3.75(minor isomer) and 3.93(mainisomer) two m, 1H δ (ppm).

The thus-obtained product (8 g, 40 mmole) was then oxidized in 100 ml ofCH₂Cl₂ with 16 g of pyridinium chlorochromate at room temperature andovernight. After addition of ether (200 ml), the mixture was filteredand distilled at a bath temperature of 130°/0.4 hPa, to obtain 2.1 g(26%) of the desired product as a mixture of 3 isomers in the ratios of12:12:15.

Odor: green, aldehyde. MS: 194 (M⁺, 4), 179(5), 153(7), 125(32), 83(26),69(100), 55(31), 41(47); 194 (M⁺, 7), 179(5), 151(9), 125(14), 83(21),69(100), 55(22), 41(38); 194 (M⁺, 6), 179(3), 151(6), 125(10), 83(18),69(100), 55(24), 41(38) (main isomer); ¹H-NMR (mixture): 0.84(main) and0.87(minor) (two d, J=7 Hz, 3H); 0.97 and 0.975 (two s, 6H); 3.31(dtr,J₁=6.8, J₂=1 Hz, 3H); 5.1(dq, J₁=16, J₂≈1) and 5.17(dq, J₁=10, J₂≈1,1H); 5.82-5.97(m, 1H) δ (ppm).

EXAMPLE 11 Preparation of(4,6,6-trimethyl-1-cyclohexen-1-yl)-2-buten-1-one

This compound was prepared using the procedure described in Example 10,replacing 4,6,6-trimethyl-1-cyclohexene-1-carbaldehyde (10.9 g, 72mmole) for 2,2,4-trimethyl-1-cyclohexanecarbaldehyde. The desiredproduct was obtained, after distillation at a bath temperature of130°/0.5 hPa in a yield of 80% in the form of a product having a purityof 70%.

MS: 192 (M⁺, 27), 177(100), 135(19), 121(23), 81(29), 69(86), 55(18),41(78); ¹H-NMR: 0.98(d, J=6.3 Hz, 3H); 1.08(s, 3H); 1.19(m, 1H); 1.30(s,3H); 1.42(m, 1H); 1.76(m, 1H); 1.88(m, 1H); 1.88(dd, J₁=7.3 Hz, J₂=1.6Hz, 3H); 2.27(m, 1H); 6.42(dd, J₂=2.4 Hz and 5.6 Hz, 1H); 6.45(dq,J₁=14.8 Hz, J₂=1.6 Hz, 1H); 6.74(dq,J₁=14.8 Hz and 7.3 Hz, 1H) δ (ppm);¹³C-NMR: 18.2(q); 22.1(q); 24.5(d); 28.3(q); 28.4(q); 34.8(s); 34.9(t);49.1(t); 130.7(d); 137.0(d), 142.5(d); 146.9(s); 194.6(s) δ (ppm).

EXAMPLE 12 Preparation of1-(4,6,6-trimethyl-1,3-cyclohexadien-1-yl)-2-buten-1-one

32 g of 4,6,6-trimethyl-1,3-cyclohexadiene-1-carbaldehyde [preparedaccording to A. F. Thomas et al., Helv. Chim. Acta, 59 (1976), p.2261-7] in 80 ml of THF were added dropwise to a Grignard compound whichhad been prepared beforehand from 6 g of magnesium turnings and 32 g of1-bromo-1-propene in 120 ml of THF. The temperature was maintained at20° with a water bath during the addition, after which the mixture washeated and kept at reflux over 30 minutes. The reaction mixture waspoured into an ice/water ixture and then extracted with ether. Theorganic phase was washed to neutrality, dried and concentrated. Thecrude product was then oxidized with 210 g of activated manganesedioxyde (see Houben Weyl, Vol. 7, 1, page 178, 1951; E. M. Goldman, Org.Chem., 34, 1979, 1969) in 200 ml of petroleum ether.

After filtration and evaporation of the solvent, 17 g of a productconstituted of several compounds and having a boiling point of 42-80°/10Pa were obtained. The desired (Z)- and(E)-1-(4,6,6-trimethyl-1,3-cyclohexadien-1-yl)-2-buten-1-one wereisolated by preparative gas chromatography. The analytical data were asfollows:

(Z)-1-(4,6,6-trimethyl-1,3-cyclohexadien-1-yl)-2-buten-1-one

MS: 69(100); 121(59); 41(40); 149(32); 105(27); 190(26); 91(17); 39(13);77(11); 79(11); NMR (CDCl₃): 1.2 (s, 6H); 1.85 (broad s, 3H); 1.85 (d,J=6,5 Hz, 3H) superposed on 2.05 (m, 2H); 5.7-6.8 (H vinyl, 4H) δ (ppm).

(E)-1-(4,6,6-trimethyl-1,3-cyclohexadiene-1-yl)-2-buten-1-one

MS: 69(100); 121(57); 41(33); 190(27); 105(23); 91(13); 39(13); 175(11);NMR (CDCl₃): 1.17 (s, 6H); 1.86 (d, J=5 Hz, 3H); 1.84 (broad s, 3H);2.05 (broad s, 2H); 5.77 (broad d, J=6 Hz, 1H); 6.38 (d, J=15 Hz, 1H,superposed on signals of 2 other protons) δ (ppm).

EXAMPLE 13 Preparation of a Floral-Green Type Accord

A base type accord was prepared from the following ingredients:

Ingredients Parts by weight Benzyl acetate 10 Phenylethyl acetate 50 10%Undecylenic aldehyde* 10 10% C12 aldehyde 10 Methyl cinnamate  5Citronellol 200  Eugenol 10 Geraniol 150  Iralia ®¹⁾ total 40 Linalol100  Lorysia ®²⁾ 50 10% Rose oxide*  5 Phenethylol 260  Phenylhexanol 50Polysantol ®³⁾ 10 Total 960  *in dipropylene glycol ¹⁾methyliononesmixture; origin: Firmenich SA, Geneva, Switzerland ²⁾mixture of cis- andtrans-4-(1,1-dimethylethyl)-1-cyclohexyl acetate; origin: Firmenich SA,Geneva, Switzerland³⁾3,3-dimethyl-5-(2′,2′,3′-trimethyl-3′-cyclopenten-1′-yl)-4-penten-1-ol;origin: Firmenich SA, Geneva, Switzerland

When there were added to this base type composition 40 parts by weightof a 10% solution of(E)-1-(4,6,6-trimethyl-1,3-cyclohexadiene-1-yl)-2-buten-1-one indipropylene glycol, this very floral accord acquired a woody connotationand a fruity-spicy undernote. The perfumers could also perceive, in thefloral note of the composition, a touch of carnation which was notpresent in the base composition.

EXAMPLE 14 Preparation of a Floral-Green, Woody-Fruity Accord

A base type accord of the above mentioned type was prepared from thefollowing ingredients:

Ingredients Parts by weight Benzyl acetate 15 Styrallyl acetate 10 10%(Z)-3-hexenol acetate* 25 γ-Decalactone  2 Dihydroeugenol  5 Galbex ®¹⁾ 5 Habanolide ®²⁾* 130  Hedione ®³⁾ 150  Iralia ®⁴⁾ 45 Iso E Super⁵⁾ 35Isopentyrate⁶⁾  3 Lavandin oil 15 10% Liffarome ®^(7)*)  5 (Z)-3-Hexenolsalicylate 120  Scentenal ®⁸⁾ 10 10% Trifernal ®⁹⁾*  5 γ-Undecalactone 5 Bergamote base, synthetic¹⁰⁾ 100  Lily of the valley base,synthetic¹⁰⁾ 175  Wardia ®¹¹⁾ 90 Vert de lilas¹²⁾ 10 Ylang-ylang 15Total 980  *in dipropylene glycol ¹⁾galbanum base; origin: Firmenich SA,Geneva, Switzerland ²⁾mixture of 1-oxa-12-cyclohexadecen-1-one and1-oxa-13-cyclohexadecen-2-one; origin: Firmenich SA, Geneva, Switzerland³⁾methyl dihydrojasrnonate; origin: Firmenich SA, Geneva, Switzerland⁴⁾see example 2 ⁵⁾origin: International Flavors & Fragrances, USA⁶⁾1,3-dimethyl-3-butenyl isobutyrate; origin: Firmenich SA, Geneva,Switzerland ⁷⁾(Z)-3-hexenyl methyl carbonate; origin: InternationalFlavors & Fragrances, USA ⁸⁾mixture of 8- and9-methoxy-tricyclo[5.2.1(2.6)]decane-3(4)-carbaldehyde; origin:Firmenich SA, Geneva, Switzerland ⁹⁾3-phenylbutanal; origin: FinnenichSA, Geneva, Switzerland ¹⁰⁾origin: Firmenich SA, Geneva, Switzerland¹¹⁾rose type composition; origin: Firmenich SA, Geneva, Switzerland¹²⁾(2,2-dimethoxyethyl)benzene; origin: Firmenich SA, Geneva,Switzerland

When there were added to this floral base-type composition 20 parts byweight of a 10% solution of(E)-1-(4,6,6-trimethyl-1,3-cyclohexadiene-1-yl)-2-buten-1-one indipropylene glycol, the perfumers could observe that the lactonic aspectof this accord is intensified, resulting in a nice fruity connotation.Likewise, the floral accord and the green notes are rounded off. Therecould furthermore be remarked a slightly woody connotation and anundernote of the mirabelle type, nice and very fruity, which wastypically confered by the above compound according to the invention.

What is claimed is:
 1. A method to improve, enhance or modify the odorof a perfume or a perfuming composition, which method comprises addingto said perfume or composition a compound according to the generalformula (1):

in which formula the dotted lines indicate a single or a double bond, nand m are 0 or 1, R¹ is hydrogen or an acyl group —C(O)R³, R³ being alinear or branched alkyl or alkylene group from C₁ to C₈, or asubstituted or unsubstituted phenyl group, the oxygen atom being boundto the adjacent α-carbon atom by a double bond in the case where n is 0and by a single bond in the case where n is 1, R² is hydrogen or alinear or branched alkyl, alkenyl, or alkoxy group from C₁ to C₈, or R²is an alkenoxy group which is linked to the group R¹ to form a1,3-dioxolane cycle having 5 to 7 ring members, provided that1-(4,6,6-trimethyl-1-cyclohexen-3-yl)-2-buten-1-one and4,6,6-trimethyl-1,3,-cyclohexadiene-1-carbaldehyde are excluded.
 2. Themethod according to claim 1, wherein the compound is of the generalformula

wherein R⁴ is a linear or branched alkyl group from C₁ to C₈ or asubstituted or unsubstituted phenyl group and the dotted line representsa single or double bond.
 3. The method according to claim 1, wherein thecompound is of the general formula

wherein R⁵ and R⁶ can be identical or different and are hydrogen or alinear branched alkyl group from C₁ to C₆ and n is an integer from 1 to3, and the dotted line indicates a single or double bond.
 4. The methodaccording to claim 1, wherein the compound is of general formula

wherein R⁷is a linear or branched alkyl or alkylene group from C₁ to C₄,and the dotted line indicates a single or double bond, provided that1-(4,6,6-trimethyl-1-cyclohexen-3-yl)-2-buten-1-one is excluded.
 5. Themethod according to claim 1, wherein the compound is of the generalformula

wherein R⁷ is a saturated or unsaturated, linear or branched hydrocarbonradical from C₁ to C₄, in the form of an isomer of the configuration (E)or (Z), or a mixture of both.
 6. The method according to claim 5,wherein there is used a mixture containing at least 90% by weight of(E)-1-(4,6,6-trimethyl-1,3-cyclohexadien-1-yl)-2-buten-1-one and 10% orless by weight of(Z)-1-(4,6,6-trimethyl-1,3-cyclohexadien-1-yl)-2-buten-1-one.
 7. Themethod according to claim 1, wherein the compound is of the generalformula

in which R⁷ is a saturated or unsaturated, linear or branchedhydrocarbon radical from C₁ to C₄, in the form of an isomer of theconfiguration (E) or (Z), or a mixture of both.
 8. Perfuming compositionor perfumed article, containing as perfuming ingredient a compoundaccording to claim
 1. 9. Perfumed article according to claim 8, in theform of a perfume or cologne, a soap, a bath or shower gel, a shampoo orother hair care product, a deodorant or antiperspirant, an airfreshener, a cosmetic preparation, a detergent or fabric softener or anall-purpose cleaner.
 10. A compound according to the general formula

wherein R⁴ is a linear or branched alkyl group from C₁ to C₈ or asubstituted or unsubstituted phenyl group, and the dotted linerepresents a single or double bond.
 11. A compound according to theformula

wherein R⁵ and R⁶ can be identical or different and are hydrogen or alinear or branched alkyl group from C₁ to C₆ and n is an integer from 1to 3, and the dotted line indicates a single or double bond.
 12. Acompound according to the general formula

wherein R⁷ is a linear or branched alkyl or alkylene group from C₁ toC₄, and the dotted line indicates a single or double bond, provided that1-(4,6,6-trimethyl-1-cyclohexen-3-yl)-2-buten-1-one is excluded.
 13. Acompound according to the general formula

in which R⁷ is a saturated or unsaturated, linear or branchedhydrocarbon radical from C₁ to C₄, with the proviso that R⁷ is notmethyl, in the form of an isomer of the configuration (E) or (Z), or amixture of both. 14.(E)-1-(4,6,6-Trimethyl-1,3-cyclohexadien-1-yl)-2-buten-1-one. 15.Mixture containing at least 90% by weight of(E)-1-(4,6,6-trimethyl-1,3-cyclohexadien-1-yl)-2-buten-1-one and 10% orless by weight of(Z)-1-(4,6,6-trimethyl-1,3-cyclohexadien-1-yl)-2-buten-1-one.
 16. Acompound according to the general formula

in which R⁷ is a saturated or unsaturated, linear or branchedhydrocarbon radical from C₁ to C₄, in the form of an isomer of theconfiguration (E) or (Z), or a mixture of both.
 17. Perfumingcompositions or perfumed articles, containing as a perfuming ingredienta compound according to claim
 5. 18. A perfumed article according toclaim 17, in the form of a perfume or cologne, a soap, bath or showergel, a shampoo or other hair care product, a deodorant orantiperspirant, an air freshener, a cosmetic preparation, a detergent orfabric softener, or an all purpose cleaner.